A 0.5-20GHz quadrature downconverter
A quadrature downconverter with 4GHz IF bandwidth and working over the 0.5–20GHz RF frequency range has been designed, fabricated, and tested. The downconverter uses a frequency doubling and dividing scheme to generate quadrature local oscillator signals from 0.5–17GHz and a pair of Gilbert-cell mixers to perform downconversion. When the IF outputs are combined with a commercial quadrature hybrid, the mixer achieves an image rejection ratio greater than 35dB over the entire band with no on-chip calibration or tuning. The active die area is approximately 0.5 x 1 mm^2.
Additional Information© 2008 IEEE. We appreciate the help of Prof. David Rutledge, Prof. Ali Hajimiri, Glenn Jones, Hamdi Mani, Aydin Babakhani, Florian Bohn, Hua Wang, and Yu-Jiu Wang. The tested circuits were processed by IBM under the Trusted Foundry Program with sponsorship of Dr. K. Johnson of the US Naval Observatory. Finally, we would like to thank the reviewers for their helpful suggestions.
Published - 04662740.pdf